Diamond-like carbon (DLC) and Nitrogen-doped diamond-like carbon (N-DLC) films were synthesized by glow discharge plasma enhanced chemical vapor deposition (PECVD) using a hybrid ion beam system. The microstructure and surface topography of films were characterized by Raman spectroscopy, X-ray photoemission spectroscopy and scanning probe microscopy. The electrochemical performance of the films was examined by an electrochemical workstation. Results indicate that the surface of all the deposited films is very smooth with low roughness. Nitrogen doping enhances the clustering of sp² sites and results in the formation of C-N bond, meanwhile, increases the amount of C-O bond and the surface active sites of films. N-DLC film electrode shows a wide potential window range over 4.5 V, lower background current (0.3±0.2 μA/cm²) in H₂SO₄ solution. N-DLC film electrode with good repeatability and stability displays significantly current response and nearly reversible electrode reaction in K₃Fe (CN) ₆ solution. Furthermore, the electrode reaction is controlled by diffusion process.

Thin AZ31 magnesium alloy sheet is laser-shock-formed (LSF) by means of a Nd-YAG pulse laser beam with a maximum output energy of 12.5 J. The surface morphology and microstructure in the shocked zone were characterized by optical microscopy and high resolution transmission electron microscopy. The results show that, periodic ripple structure with clear texture and nanoscale space appeared on concave in LSF shocked zone, with which the growth of sub-grains, nanocrystallites and deformation twins might be accompanied. The distribution of residual stress in the shocked concave was analyzed, and the relevant mechanism concerning ripple phenomenon and nanocrystallites formation during LSF was also discussed.

A Ni-Co-Al superalloy was prepared by powder metallurgy(mechanical alloying + hot-press sintering). Then the effect of hot-press sintering temperature on the mechanical property of the alloy at ambient temperatures and the tribological performance at 800℃ were investigated. Results show that the density, hardness and compressive strength of the alloy increase with the increase of sintering temperature, while these properties change little when the sintering temperature above 1200℃. As the sintering temperature increases, the tribological performance of the alloy at 800℃gets better. The examination of the worn surface morphology by SEM and XPS found that a glaze-like oxide scale formed on the worn surface, which seemed to be beneficial to the tribological performance. The adhesive strength between the oxide scale and the substrate affects the tribological performance of the alloy, which may relate to higher density induced by higher sintering temperature. The examination of the worn surface with 3D non-contact surface mapping profiler exhibits that the depth of abrasion grooves is dependent on the hot-pressing temperature.

Nanocrystallined cobalt zinc ferrite was prepared by polyacrylamide gel process, and then the polypyrrole (PPy)-cobalt zinc ferrite composites were synthesized by in-situ chemical polymerization. The microstructure and morphology of the composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The magnetic and microwave dielectric properties of the composites were measured by vibrating sample magnetometer (VSM) and vector network analyzer of E5071C. The results show that the products are composites consisted of pure PPy and PPy-Co_0.5Zn_0.5Fe₂O₄, and the average particle sizes of PPy and PPy-Co_0.5Zn_0.5Fe₂O₄ are about 200 nm and 180 nm, respectively. The saturation magnetization (M_s) and remanent magnetization (M_r) of the Co_0.5Zn_0.5Fe₂O₄ are 65.95 emu/g and 15.44 emu/g, respectively, and they are greater than that of PPy-Co_0.5Zn_0.5Fe₂O₄, but the coercive force (H_c) of the Co_0.5Zn_0.5Fe₂O₄ is smaller than that of PPy-Co_0.5Zn_0.5Fe₂O₄. Owing to the introduction of Co_0.5Zn_0.5Fe₂O₄ ferrites into the PPy matrix, the dielectric loss (tanε=ε''/ε') of the PPy is greater than that of the PPy-Co_0.5Zn_0.5Fe₂O₄, but the reflection loss of the PPy is smaller than that of the PPy-Co_0.5Zn_0.5Fe₂O₄. The maximum reflection loss of the PPy–Co_0.5Zn_0.5Fe₂O₄ composite is about -16.4 dB at 15.2 GHz with a bandwidth of 2.5 GHz.

The copolymer of polythiophene derivative (P3HT-co-P3AcET) containing alkyl and ester side chain was prepared by FeCl₃ oxidative coupling copolymerization. The chemical structure of the resulted copolymer was characterized by GPC, ¹H NMR, et al. The assembling of P3HT-co-P3AcET nanostructures was performed by mixing solvents, of which toluene was adopted as the good solvent, while dioxane or methanol as the poor solvent. The nanostructures of P3HT-co-P3AcET with different morphologies were obtained by adjusting the ratio of the mixed solvents and the aging time. The SEM results show that the assembling of P3HT-co-P3AcET tends to produce nanofiber bundles with dioxane as the poor solvent, and spherical nanoparticles with methanol as the poor solvent in the mixed solvents, respectively. For which a higher lipophilic value of dioxane rather than that of methanol may be responsible. The arrangement manner of the copolymer chains was analyzed by ultraviolet visible light absorption spectrum. The results show that the different arrangement manners of the copolymer chains can give rise to different morphologies in nanoscale, such as nanofiber bundles and spherical nanoparticles. Finally the mechanism concerning the formed nanostructures of the assembled copolymer was also preliminarily explored.

A tungsten carbide particles reinforced steel matrix composite was fabricated by spark plasma sintering (SPS) technique, and then the composite was remelted in a vacuum tube furnace. The effect of remelting temperature on interface reaction was investigated meticulously. The results show that the interface reaction could occur when the matrix was still in solid state, the thickness of interface reaction layer increased with the increasing temperature. The interface reaction product, Fe₃W₃C, was resulted from the following two step reactions: firstly the reaction 2WC→W2C+C would occur within tungsten carbide particles at 1314℃, then the W₂C would react with Fe to produce Fe₃W₃C at temperatures above 1341℃.

The reaction processes of mineral admixtures in a cement-silica fume-fly ash ternary cementitious system aged for different time were quantitatively studied by means of selective dissolution and non-evaporative water content methods. To determine separately the degree of pozzolanic reaction for silica fume in the ternary system, fly ash was replaced by the inert quartz powder with the same fineness and same dosage in order to eliminate the dilution effect and heterogeneous nucleation effect. Then the reaction degree of fly ash can be calculated from the total reaction degree of all the admixtures in the system. The test results demonstrated that only 1 d after the beginning of the hydration, the pozzolanic reaction for silica fume already started, and the reaction exhibited a fast rate in the early stage but a slow one in the later stage. However, the same reaction with a rapidly increasing rate for fly ash just began only 7 d after the beginning of the hydration. In the ternary cementitious system, the hydration degrees for both silica fume and fly ash were reduced with the increasing fly ash content.

Amorphous ribbons Fe_73.5Si_13.5-xGe_xB₉Cu₁Nb₃(x=3, 6) were prepared by a normal single copper wheel melt spinning technique in atmosphere, which then were isothermally annealed at 470℃、510℃、550℃ and 590℃ respectively for 1 h in a vacuum furnace. The microstructure and crystallization kinetics of the ribbons were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC) measurements. While the crystallization activation energies of amorphous ribbons were calculated by using Kissinger, Ozawa and Augis-Bennett models based on differential thermal analysis data. The local Avrami exponent n for primary crystallization was calculated by using Johnson-Mehl-Avrami (JMA) equation. The significant variation of local Avrami exponent n with crystallization volume fraction α demonstrated that the primary crystallization kinetics of amorphous ribbons varied at different stages. In the initial stage, the crystallization mechanism was diffusion controlled bulk crystallization with three dimensional nucleation and grain growth, while the nucleation rate deceased with time. In the following stage, it was surface crystallization with one dimensional nucleation and grain growth, while the nucleation rate was near zero. The average sizes D of α-Fe (Si, Ge) grains for the samples annealed at 510℃、550℃ and 590℃for 1 h in a vacuum furnace were less than 15 nm as confirmed both by XRD and TEM measurements.

For the delta process (DP) of GH4169 high temperature alloy, the effect of d phase content on its hot deformation behavior and evolution of microstructures was studied systematically by isothermal compression test with a strain rate range 0.005-0.1 s^-1 at temperature range 950-1010℃. The results indicated that the true stress–true strain curves for GH4169 alloys with different initial d phase contents of 0, 3.65% and 8.14% may be characterized with the feature of single peak curves, and the constitutive equation could be all expressed by a hyperbolic-sine Arrhenius-type equation. The corresponding activation energies of deformation were 441.3, 445.8 and 487.7 kJ/mol, respectively. The main soft mechanisms for GH4169 alloys with different initial d phase contents during hot working were all dynamic recrystallization (DRX). As the increase of δ phase content, the critical strain and grain size of DRX decreased, and the fraction of DRX increased. The DRX nucleation for the solution treated alloy might mainly rely on the bulging of original grain boundaries, while the boundaries between the d phase and matrix were the nucleation sites for DRX in the pre-precipitated GH4169 alloys. Thus, the existence of d phase can stimulate the occurrence of DRX.

The friction and wear performance of H13 steel after a duplex pack boriding treatment assisted by high-energy shot peening the un-borided one were investigated. The experimental results show that a layer of monophase of Fe₂B formed on H13 steel after the two-step pack boriding treatment assisted by high-energy shot peening; the high-energy shot peening can remarkably enhance the boriding process. The wear rate at elevated temperature of the boronized H13 steel may be reduced up to 30% in comparison with that of the bare steel. The oxide scales formed on the wear surface of the boronized steel and the bare steel all are Fe₂O₃. A wear mechanism concerning the elevated temperature wear is proposed that the boronized H13 steel may firstly suffered from fatigue flake of boride layer and subsequently oxidation wear due to its high hardness and excellent oxidation resistance. However, the elevated temperature wear mechanisms of the bare steel are synergistically oxidation wear and abrasive wear.

An Fe/Al₂O₃ nanocomposite was prepared by high energy ball milling method, and which then annealed at 700^oC for 0.5 h in Ar atmosphere. The effect of annealing on the microstructure, magnetism and microwave-absorption properties of Fe/Al₂O₃ nanocomposite has been investigated. It follows that the annealing resulted in increasing grain size, decreasing lattice defects and releasing the residual microstrain; meanwhile, decreasing the intensity of photoluminescence peaks of Al₂O₃ significantly, therewith the peaks at 398 nm and 484 nm exhibit a blue shift. An optimal reflection loss of -11.4 dB at 15.5 GHz was measured for a 7.7 mm thick layer of as-milled composite powder mixture with paraffin. However, the annealing treatment could remarkably enhance the dielectric loss, magnetic loss and microwave absorption performance of the composite, leading to an optimal reflection loss of -35.5 dB at 17 GHz for a layer thickness of 6.4 mm for the annealed composite.

The preparation parameters were systematically optimized in order to produce an appropriate micro-arc oxidation (MAO) coating on pure titanium. Then the optimized MAO ceramic coating was subjected to alkali treatment. The bioactivity of the alkalized coating was evaluated by immersion test in a simulated body fluid (SBF) for certain times. The porosity, pore density and pore diameter of the MAO coatings were examined by formula scoring method. The results show that the best MAO may be produced with the following electrical parameters: positive voltage 400 V, duty ratio 60%, frequency 550 Hz, and oxidation time 25 min. The results of examination by XRD, SEM and EDS show that a uniform porous anatase TiO₂ coating grew on titanium with porosity 12%, pore density 0.70×10⁸, and a mean pore diameter 3 μm. The alkalized coating treated by alkali method was completely covered by bone-like apatite when it was cultured in SBF for 14 days. The calcium deficiency like apatite with a composition similar to that of human bone grew on the coating exhibits excellent bioactivity. But the apatite could dissolve with the extension of the culturing time.